a festool lunch box planer idea has been talked about here before. it is one of the only few tools that festool dont have in their system for site work. i would buy one if they made it.
if you put a changable head in there ( or seperate head after the cutting head) for sanding that would be great. i would like it to ossilate back and forth to minimise head build up  etc.

The Wide Belt sander is my most prized machine that I own.  - besides custom work/cabinets, I build a lot of entry and passage doors, stair parts,  and even for dimensioning rough stock to .001" accuracy,  nothing beats a widebelt, except a BETTER widebelt.

I've used 24" WB Sanders, and they're too big to be anything but stationary,  but not big enough for professional use (unless you're a luthier or for other specific uses)

37" 43" and 52" are the normal sizes and these monsters are always 2500-4000lbs, require massive 3 phase power, an 80 gal 2 stage compressor, and enormous dust collection capability.

however, if a true WIDEBELT,  (not a drum sander, those are a joke) Wide Belt sander were designed with 13" width, perhaps a 36-40" belt length, optical tracking system that was electromechanically oscillated and adjusted,  and typical Festool innovation and design,  I think something truly AMAZING could be achieved,  and once in for all,  the "HOLE" in the Festool system would be filled...
add an optional planer head and "mobility kit" for the machine, and keep it under $3000 and 150lbs (base price) and I would buy at least one

I get the feeling there are some here who don't understand what a widebelt is/does?
Felder are among the finest:
http://www.felderusa.com/us-us/products/wide-belt-sanding-machines/wide-belt-sander-fw-1100.html 

Timesavers are the quintessential "timesavers" of most woodworking shops
 http://www.timesaversinc.com/

and believe it or not, Grizzly, provides a very good machine for the money in their wide lineup or WIdeBelt Sanders.
If I could have any 1 new widebelt under $20k, it would probably be another Grizzly...
the 43" single head machine I had in my old shop ran 5 yrs or HARD use without failing with the exception of a $1.77 spring which was fixed in only 3 days...
http://www.grizzly.com/products/category.aspx?key=550000

so...  if planers can be made into "travel size" mobile machines,  -then why can't a widebelt?  with Festools Relentless pursuits of IDEAL form and function, I think they could certainly come up with one.
and again, if it had an optional spiral index cutterhead,  perhaps another moulder head and other standard BRILLIANT Festool accessories (gang rip saw?)
it could really be the core unit of a full millwork shop in a semi portable unit.

at least consider it, Festool!