Rainbow offers the iKey 300, an USB crypto token with 32k memory and support for RSA keys up to 1024bit key length.
The iKey 3000 is fully supported by OpenSC and is well tested.
The smart card inside is a starcos card by Gieseke and Devrient.
One minor feature of Starcos is that a pin can only be unblocked if it is blocked. For this reason the regression test pin0002 fails, but this is a harmless and known issue, so please ignore.
Rainbow iKey 3000 is bundled with StarSign? software by A.E.T. which follows the PKCS#15 standard. Thus key can be initialized with either OpenSC or StarSign? and will work with both.
Documentation for the Starcos Smartcard is available to the public. Send those nice folks at G&D an email and they will send you the latest manual.
Cyprotect sells Rainbow iKey 3000 tokens at 68 Euro per piece.