Boot 2010 iMac from 2007 MacBook Pro's drive?
It may be possible, but not recommended. While you don't really have to worry about drivers so much - there may be minor incompatibilities. That is if you get it to boot - especially if the MacBook Pro isn't running the latest version of the OS thats after whatever originally came on the iMac. 

System updates can be used across machines, but when the install is being done it does check the hardware. You may end up installing iMac specific things on your MacBook Pro, which may cause issues. 

You really have two routes:


Buy a new MacBook Pro instead, and an external monitor. Therefore you have the same machine, and can go wherever. 
Sync the two machines using items like Dropbox, etc. I understand maybe application differences, but thats a very small issue (almost a non issue). Keep most of your files on dropbox, and everythings always in sync.


I would go (and do use) the second solution. My primary machine is a 27" iMac, but I constantly use my wifes 13" MacBook Pro when going out or not at my desk. I then keep most all active documents in Dropbox and sync between. Both are outfitted with the software I need (in my case, Aperture, TextWrangler, Xcode, etc).