The only sites I've seen that carry any B5 VCDs are limited to a couple of TV movies - The Gathering, In the Beginning and (just recently) Thirdspace. Since the first two are available on one (U.S., Australia/NZ) or two (U.K.) DVDs instead of four VCDs, I don't see much point in buying them.
The movies sell for around $13 each, plus shipping. Presumably two episodes would cost about the same, so we're looking at $260 a season. At those prices you could buy the upcoming S1 DVD set and have enough money left over to buy a DVD player if you don't already have one.
I saw a post from someone who said he recently bought Crusade on VCD from a retailer, and I've asked him for a URL because I know KoshN is looking for them. If I get an address I'll be happy to pass it along, but I would have to advise waiting a month or two to see if we get an official announcement from Warner Bros. on the DVDs before you invest any money in VCD.
Regards,
Joe