Dan, you can get blotter books at www.alles-foto.de (Brenner Foto Versand) here in Germany.
They are called "Foto-Loeschpapier-Buch" and cost about $24 USD. They are ring bound, 30X37 centimters and can dry up to 18 prints simulataneously. They are ph neutral and the pages are buffered with a 3% Calcium carbonate.
If you need help ordering, let me know.
Just found this at www.silverprint.co.uk
Wood & acid free, heavy 300 gsm 17 x 24 in sold in packs of 10 and 50 sheets. The idea of drying in blotters is to put the FB print through several stages of drying, each time with fresh dry blotters, so you need plenty of them. A suggested sequence is squeegee the wet prints and then put them into the first set of blotters. Place them under reasonable pressure. Leave them for 20 minutes, then take them out and put them into new blotters for 2 hours. Finally, put the prints into more fresh blotter and leave till dry, which is probably overnight. It sounds rather involved, but should result in prints that need no futher flattening.
37 891 Archival Blotter 300 gsm 17x24 in / 10 3.95
38 679 Archival Blotter 300 gsm 17x24 in / 50 15.82
Prices are in Pounds including VAT