not sure on the max #, but when i set up my loc i asked the loan officer if multiple cards were ok. she sounded uneasy about responding, but did say they do have members that have multiple cards.
now my strategy is since i have the nsa visa with the 6 month promo rate (which is the same as thier plat visa), i'm going to wait out my 6 months and then app for the plat. two reasons.
1. i'll have the 6 months history behind me and the max on the platcard is 40k (maybe i'll qualify).
2. my intro rate of 6.99 for 6 months will be up and since i'll have a balance on it (my best rate by far), i'll (if i get it) move some more debt to it.