Making enlarged proof sheets. Is there a holder?

Besides aligning rows of 120 negs in an 8x10 glass carrier, is there another way to make enlarged proofs with an enlarger?
I'd like to make 24" prints for some portraits, having 10 negs on one print. This would be a final print, not a proof for analyizing.

I know saunders makes a glassless Super-Proofer but i don't know if the negs would stay flat enough.
http://www.bhphotovideo.com/c/product/46132-REG/Saunders_175120_Super_Proofer_120.html

Is there a carrier the labs used to use for this purpose?
NO, i don't want to hear about digital alternatives.

vinny

I would make a mask out of cardboard, like mat board, with a hole cut out for each individual image, tape the cutout over each hole with a hinge of tape so it can be opened and closed, then tape the paper to the back of it, then enlarge each image separately in sequence.

I think they just align the strips in a glass carrier, as you mentioned.

I've gotten regular sized proof sheets from Duggal that are proofed in the filing page, but are sharper than I would expect from negs contact printed in the page, and I suspect what they might be doing is proofing them using an enlarger with a glass carrier at 1:1 enlargement.