HI
Iam not what you are basically looking for, cause crc is teh most simple and quite effective ioption that exists to validate the channel decoded block.
May be you can look at option of implementing (k,n) block codes where k n would match the crc bits length.
also for more simpler option you could look at even parity bits encoding scheme.
Well I suggest glancing through information theory and coding section of digital communication by sam shanmughan.
Cheers
S