Luis,
There's a good lightweight shelter roundup (by Will Rietveld) over at backpackinglight.com, but it's "premier content" meaning it's only available for subscribers. The article is a report from the September 2008 Outdoor Retailer trade show, and includes info about models coming out in the next six months. If you can wait until spring 2009, then you'll be able to evaluate new tent models from North Face and Sierra Designs (and probably other manufacturers).
http://www.backpackinglight.com/cgi-bin/backpackinglight/orsm08_lw_shelters.htmlYou'll need to make a fundamental decision about whether you want a hammock, a single wall tent, or a double wall tent. If you and your wife will share a double bag then 2 hammocks won't be viable. Do you already know whether you want single or double wall? This article (unfortunately also for subscribers only) has good evaluation of the advantages and disadvantages of single vs double wall ...
http://www.backpackinglight.com/cgi-bin/backpackinglight/double_wall_tents_review_summary.htmlHere are a few bits of info from Will's article (in case you aren't a backpackinglight subscriber) that might help you make a decision...
There are several models of 2 man double-wall tents on the market now that are <4.25 pounds and plenty comfortable. There will be several more models available in spring 2009. You can get as low as 3.5 or 3.75 pounds for a double wall 2-person tent by giving up some features/space. If you decide on a double-wall tent, you should look for options in the sub-4.25 pound range, with opportunity to go as low as 3.5 pounds.
Henry Shires (tarptent.com) and GossamerGear.com are very well respected for light-weight single-wall enclosed tarp tents (i.e. bug proof).
If you want a double wall tents Will's article points out a few lightweight choices:
MSR Carbon Reflex 2 weighs three pounds, four ounces and costs US$500(I'm not sure if it's available yet).
"REI's updated T-series Quarter Dome tents (T2 shown, 4 pounds, 2 ounces, US$259), available in 1-, 2-, and 3-person versions, are well-designed, lightweight, and value priced." (available spring 2008, so already in stores).
For release in spring 2009: "We have always liked Sierra Design's easy to set up tents, but they have always been a bit on the heavy side by our standards. For spring 2009, SD has re-designed most of their extensive tent line (seventeen new tents), and six of them now come in under our weight limits. I will highlight two of them. The Lightning XT 2 (4 pounds, 7 ounces, US$289), a two-person freestanding double-wall tent, has two side entry doors with vestibules, and provides thirty square feet of floor space plus twenty-one square feet in the vestibules. The VaporLight 2 (3 pounds, 12 ounces, US$329) is also freestanding and has front entry and vestibule. Floor space is 25.5 square feet, and the front vestibule adds another 8 square feet of protected area."
"Not to Be Outdone, The North Face Introduces Nineteen New Tents for Spring 2009. Among The North Face's rollout of new tents for spring 2009, the Flight Series of single-wall tents are the lightest. The lightest in the Flight Series are the Dyad 22 (3 pounds, 9 ounces) for two people. The Dyad has a floor area of 36 square feet plus 4.5 square feet in the vestibule, lots of headroom at the front, and a good high/low ventilation system."
"Mountain Hardwear's Helion 2 Features Cutting Edge Lightweight Components. The new Helion 2 tent (3 pounds, 5 ounces, US$395), available now, is their lightest two-person double-wall tent"
And your easy question... Jim and I carry a two person tent on top of a rear rack. If we eventually switch from RearRack&Pannier system to Carousel/EpicDesign system, then Jim would carry the tent on his handlebars and I would carry our 2-person Nunatak top-bag on my handlebars.
Jim and I have switched from normal-load to light-load, but have not gone to ultra-light. One of our last hold-outs is a four pound double-wall tent. Although much heavier than the tarp-tent options, we are quite attached to the bomb-proof convenience it provides. We have also chosen to pay the weight penalty for two doors rather than a single front door because of the convenience and nice sense of space - not important for occasional nights out, but we've found it meaningful when out for a month or two at a time. If most of your trips will be solo, then you might want to save the half-pound or so by choosing a single-door tent.
One more thing to think about when you choose... Will you be stealth camping (camping where it's not technically legal)? If so, then some models are undesirable because of the bright colors. For example, the REI Quarterdome fly is a nice moss-green. The MSR Hubba Hubba fly is an attention-grabbing bright yellow. Henry Shires tarp-tents are a nice dull gray.
If I were you, I'd wait and look at the new offerings from North Face and Sierra Designs before choosing. Both of those companies have a long history of nice tents, and it sounds like they have redesigned their whole tent line-ups to be lighter weight.
Hope this helps,
AmyL
Palo Alto, CA