This question would be best answered for the time period of our first colonized planet, which will most likely be Mars. With the thinner atmosphere, weaker gravity, low oxygen, and the bodily damage possible from the sun, some sort of protective suit is a must outside of colony pods. But the size of current space worthy suits would hinder in-atmosphere work that requires more delicate handiwork. Not to mention, there is some kind of atmosphere, so a full-on space suite would be a tad bit overkill. So what would be the likelihood of a skintight suit designed only for Mars survival?
It's called a Mechanical Counter Pressure suit (MCPS). They fit and look like a divers dry suit that's two sizes too small. Check out the MIT project that is underway.
They have been a staple of sci-fi since the 1940's and were a serious contender for the Apollo space program. The airbag style suit that was settled on (and is in use to this day) was chosen purely because the effects of air pressure on a human body were known, but the effects of mechanical counterpressure in a vacuum were not. Having more experience now than the early days of the space programs to draw on, and knowing the limits of the fabrics available then, I am not convinced that their choice was wrong.
Professor Dava Newman models the MIT Biosuit - from http://astronomy.com/news/2007/07/one-giant-leap-for-space-fashion:
See also http://www.finalfrontierdesign.com/what-we-make/ . This image is a commercially produced MCP glove that has applications today.
1949 cover from Red Planet (Heinlein) showing two teen boys in MCP suits with insulating outerwear:
As a matter of fact, so-called "space activity suits" have been in development since 1959, although they haven't had a whole lot of success yet. There aren't enough advantages to the models that have been produced so far to displace the existing gas-pressure-based spacesuits.
Space activity suits work by pressing tight layers of fabric directly against the wearer's skin, rather than filling the suit with pressurized gas like current spacesuits do. In principle, this should permit much greater mobility than existing spacesuits do, but they're also much more difficult to get right and much more difficult to squeeze oneself into.
Currently, there's a project at MIT to create a space activity suit consisting of a single layer of cloth set with stretchy cords to provide pressure, but as far as I know, they haven't worked out all the kinks yet.
MIT in cooperation with NASA is currently working on a BioSuit project. It is specifically designed for planetary exploration and relies on mechanical counterpressure. The BioSuit is made of various layers of polymers and nylons to provide necessary pressure and protection.
Mechanical counterpressure suits (MCS) are the future of space technology and they might even replace traditional gas-pressured suits since there are many advantages to getting rid of sacks filled with gas.
The existing prototypes of MCS are lightweight and do not restrict movement as much as traditional spacesuits. They also seem to be safer when it comes to tearing (no depressurisation). A new generation of materials can make them self-healing to reduce risks even further. Scientists are also looking into using alloys and special wired structures to work as exo-skeletons. Mechanical compression has an additional benefit of slowing down the bone loss process typical for low-gravity environments.
MCS also does not need as much personalisation as traditional suits. As new technologies develop it might be possible to produce 'one size fits all' versions which will significantly reduce the costs.
So, yes, it is a very viable idea.
As other have stated, MIT (and probably others) are currently working on developing one. Given a range of 10-100 years in the future (per when we'll colonize Mars), it seems very likely that we'll have a significantly less bulky suit for casual wear. Probably skin tight. Also, as stated in the question, this suit won't have to withstand insane pressures. The trickiest parts would be radiation and temperature, which seem to already be well understood. You can have a small power source to supply electrical heat, and some sort of backpack or tank for oxygen. I see no technological reason that would prevent a wetsuit-like Mars suit.
They are very viable. Look at the BioSuit via Space.com
Instead of the bulky-looking spacesuits that astronauts wear today, a group of MIT researchers want to "shrink-wrap" the spaceflyers of tomorrow. Current spacesuits could be replaced by a pressurized but skintight suit that would allow for a much better range of motion during exploration, according to scientists at the Massachusetts Institute of Technology.
They now have a machine that "prints" the suit to fit the individual.