I too am not quite sure what you're looking for. But I assume that you're looking for a way to neatly take all of those conductors from a panel change that are too short to make it into a new panel - but dont want to have 4-5 4Sq's as a junction from old to new?
Well.... How much money you got? And how neat would you like it to be?
Use existing as a J-bx, and nipple to new.
4Sq's and remove and replace in same location with new.
Still cheap, but expediant:
14X14 NEMA 1 or 3 j-box at existing location - nipple to new.
No longer cheap - but neat:
Same as above, but with terminal blocks.
Not cheap at all - but really neat:
Same as above but with DIN rail terminal blocks.
The word "Cheap" can not be used:
Extend/repull all wiring to new panel...
"Well - I oughta....." -Jackie Gleason