We made our version of this adapter finally :-)
Unfortunately, I don't have native PL lenses to check compatibility.
Couple of standard primes fit and work fine.
Fast LOMO lenses converted to PL have issues. 28mm works fine. Other lenses (35mm, 50mm) work at short distances only (up to about 1.5m) since rear part of the optical block hits adapter body when you trying to focus further. 75mm lens doesn't fit at all due to extra element in it's rear part.
These issues are due to quite short flange focal distance of PL mount, so there is not enough room for rear parts of big lenses (old and/or fast LOMO).
Sample picture was shot with my EOS 300D and fast 28mm lens OKS10-28-1M.
Drawing shows essential dimensions that you have to check to make sure that your lens(es) fit our adapter.
This is stand-alone adapter (no any modification to you camera or lens is required). But we are working on replacement PL mount for EOS - it will accept more lenses since there will be bit more room in the rear part.