Rodney,
Yes, you can insert multiple EKU. No, there is no limit, just as there is no limit on the number of attributes in a DN, or the number of extensions in a cert. If we tried to nail down the numbers for each of these parameters, we would still be arguing over them today :-).I believe (some PKIX lawyer check me on this...) that 2459 allows any number of EKU's (wanna parse a cert with 572 EKU's, anyone? Can you say "architecturally irresponsible"?)