I wrote a base 92 encoder for the Javascript game I'm working on:

http://www.emergencevector.com/

It's pretty easy to write the decode for the 0-91 integer in Javascript.

    if (ch == "!") {
        return 57;
    } else {
        return ch.charCodeAt(0) - 35;
    }

It doesn't give you that much usable compactness over base 64, though you can easily encode a 360 degree angle with two bits of precision lost. Also, 5 base 92 characters can fully encode 32 bits of binary data. (Of course, since base 85 can do it in 5 characters.)

I'm probably going to go to typed arrays of 32 bit values. Currently, I can encode an entire ship's data in 18 bytes, of which 4 characters is a hash id.