Dear Isogeochem,
   A company called "Q Glass" in New Jersey will do custom work.  I've
had them do some custom work for me, from my drawings (with dimensions).
They will also help you with their input into the designwork.  Specially
made items are not, however,  returnable.   Also, they pack their items
very well for shipment.  Their address is below:

Q Glass
624 Route 202
Towaco
NJ 07082

Ph: (973) 335-5191
Fax: (973) 335-2057

DL Roose
US EPA