My current plan is to stumble into some music stores and ask them what they have.
Probably a good idea!
Can't hurt to gather some information before-hand, though.
Roland is considered the standard when it comes to e-drumming. You'll have to plan in at least USD 600, though, and I don't know whether the cheapest model (Roland HD-1) is okay for the price or not.
Some stores like Thomann
also sell e-drums of their own brand, but again I can't say if they're okay regarding response etc.
Regarding MIDI, most drum sets have a MIDI out on their sound modules nowadays while the triggers connect to that with TRS cables sending CV (control voltage). I'd be careful and check that, though: if the module has no MIDI out, you'll have to buy a convertor, there are models by Alesis and Roland which work equally well.
An alternative would be to go for a drum pad like the Roland Octapad or the new SPD-SX (you can probably get the old SPD-S pretty cheap now on eBay etc.) - you could also go for the Alesis Peformance Pad which is quite cheap too and has a MIDI out.
You can still connect triggers for Kick and Hi-Hat and it won't take away as much space and will be more portable.
Anyway. Even if you buy the priciest Roland set, there's still a huge difference to real acoustic drums. Although there are good sampling instruments like Addictive Drums which can sound pretty convincing in context, it's not the same for a huge number of reasons, even with the multiple pressure points on the modern Roland mesh heads and cymbals, there's just too much detail to playing the drums that can't be captured by sampling (yet?).
Hope that helped? Any further detailed questions, don't hesitate asking.