I machined a bunch of bodies for Ego feednecks a while back - remove the plastic shroud from over the feedneck, chop off the tubular portion with a 1.5" endmill, and then use a boring head (with the boring bar facing _inside_) to turn down the diameter of the 'stub' that remains. Worked great, and made for a really low profile system. I just wish I could have gotten more of the cheap Ego clamping feeds to have done more bodies! (I actually do have a single body left, but it's a right feed body that I had mistakenly done, thinking I was grabbing a centerfeed body off the shelf)
CCI does indeed have clamping vert feed bodies now, and I've had a few in stock for several weeks but still haven't had a chance to add them to the site. They use CCM feednecks (7/8"-20 thread). Pricing for just the body (no feedneck) is the same as for a standard direct feed body - $33.20. The feedneck itself is $25.
Mike also has this little gem which I just got into stock (hopefully can add it to the site this weekend):

It's essentially the same bulkhead that he welds to bodies to take the CCM feeds, but with a screw for bolting it to a stock class body. Retail is $15.