Tannoy makes some really nice monitors in every price range, some are powered too.
As for portable 24 track options you really only have 2:
Alesis HD24XR records 24 tracks of 24/48 or 12 tracks of 24/96, so a pair can be used for 24 tracks of 24/96. The HD24XR records to removable hard drives (the same kind made for a PC) and then the data is transferable to your DAW via the caddy that Alesis makes. Retail is $2000 new, 1500ish used.
Echo Audiofire 12 records 12 tracks at 24/192 but you can daisy chain a pair for a full 24 tracks of 24/192. These units record to you DAW via firewire and are Wordclock and midi compatable. Supposedly they're capable of working with Pro Tools and other DAWs. Retail is $799 new for each unit, $500 or less used.
I've been looking into 24 track location setups myself and these are virtually the only 2 options that provide 24 tracks of 24 bit audio and portability. While the Echo units offer higher sample rates they're guaranteed to be less reliable and stable than the Alesis unit. The HD24XR is basically the standard for critical location work and is built to take bumps on the road. There are a few other options in the marketplace but you're going to be spending a hell of a lot more cash for those. If you know Teddy for TS he highly recommended the HD24XR to me and uses it himself for recording symphonies with very high end mics, pres and ADCs. So I guess if it's a high enough fidelity for the most demanding of all recording environments it's probably the way to go. That's my .02, but I'm gonna talk to Teddy about it again.
Are there any options that I'm not aware of?