I'm also planning on picking up a .22 soon. I'm more interested in a semiauto, and as such am not too familiar with the revo options. In general, I'd go with whatever balances, points and fits your hand the best. As for barrel length, I'd go with whatever balances best. The long barrels (6-7"+) offer a longer sight radius, but otherwise are no more accurate than their shorter brethren. If you plan to mount a scope, the sight radius won't matter. Many target shooters go with a barrel in the 5-6" range topped with a scope.
So far I've considered the Browning Buck Mark, Ruger Mark II/III or 22/45, Beretta NEOS, Sig Trailside, or S&W 22A. All but the Sig can be had in many configurations, some relatively inexpensive.
The Browning fits my hand almost perfectly - this is probably what I'll go with. Field stripping is easy, but not as easy as the Beretta or Smith. Requires a screwdriver. Field stripping involves removing the rear sight, but supposedly it doesn't NEED to be re-zeroed each time. I've generally heard good things about reliability and accuracy with this gun.
The Ruger models don't feel as good in hand, to me. Maybe a different set of grips? Every time I've heard this gun mentioned, the difficulty of reassembling it has come up - those who have worked with them for a while say you get the hang of it eventually, but it definitely takes some practice to get proficient. I actually heard one shooter say that he sends his to his son to reassemble!
The Mark III has a magazine disconnect, a loaded chamber indicator, and an internal locking mechanism which works via the manual safety. Purists seem to prefer the Mark II, which does'nt have these safety features. There may still be some Mark II's NIB, but it's my understanding that Ruger has discontinued these (they're still listed on the Ruger website). The 22/45 has a grip molded to resemble the angle and feel of the 1911 grip, and the magazine release is located similarly to the 1911. I've generally heard good things about accuracy and reliability with Rugers.
The Smith has a very blocky grip - too big for my hands. Along with the Beretta, this is one of the easiest of the bunch to disassemble for cleaning. I haven't heard good things about the reliability of this model. I haven't looked into it very much due to the grip.
I haven't handled the Sig/Hammerli. Supposedly, it is the most consistently accurate of the bunch out of the box - Sig won't let them out the door if they don't group well at the factory. The test target/group is included with the pistol. The frame and barrel are all one piece - so no switching barrels later. I've heard RUMORS that Sig won't be distributing these much longer, so as not to distract from their own 22's.
Hope this helps.