how hard is it to just do all the hashing and stuff yourself? i dont see any checksum/hash functions explained anywhere so i am wondering if the information is publicly available
I have managed to port the already existing checksum and hashing functions to Apple hardware, and those were pretty much directly backported from assembly. The functions are fairly complicated to understand completely, but usage isn't very difficult. You should be able to find the source code in various open sourced bots that are floating around.
-Smoke
It'll be hard unless you have a solid background in reading disassembly and converting it to your own src. Most algorithms are publicly available, tks.slacktech.com.
If you have a firm understanding of the language you want to make the client in, it shouldn't be too difficult of a task... Especially since everything you need to handle the hashing is available. Plus there is documentation on almost the whole protocol available. I personally believe making a binary client is no longer a matter of skill in reverse engineering, just your understanding of programming.