Machine vices tend to be overly heavy for pillar drills with rather restricted opening given the size of the beast. Typically the moving jaw on machine vices is longer than the opening to give plenty of support to the jaws under milling loads so the base has to be in proportion to give sufficient support. Drill vices have much shorter jaws, too short in the case of many cheapies, so the opening is much greater proportion of the base size.
When considering a similar issue I seriously considered using the design for a simple adjustable planer vice published in Popular Mechanics, vol 037, 1922 , March issue on page 462 :- **LINK** as a basis for a home brewed one with suitable adjustments to size. Doesn't seem that difficult to make from standard sections glued'n screwed together if you have adequate milling facilities to make the slots. Jaw lift should be well controlled.
Being an (over)ambitious type I've decided to make a Chick style one as being neater and a touch faster in operation. More interesting to design and build to but a metric shed-load more work! But I have an adequate 6" cross vice so the need isn't pressing.
Strongly reccomend prismatic jaws on a drill vice. Mine have one horizontal Vee slot and three vertical ones of different sizes. I have prismatic ones on bot moving and stationary jaws but could easily be persuaded that only one is needed.
Clive.