For anyone who still plays Beta 1.7.3, I've made a simple mod that adds an FOV slider in the options menu from the later versions of the game.
The only noticeable difference is that the hand/item model is stretched out.
Note: this mod will not work with the new Minecraft launcher. The launcher attempts to replace the modified jar due to conflicting hashes. Please use a third-party launcher such as MultiMC to use mods for older versions.
So, have you fixed the incompatibility with Optifine? I got tired of trying to recompile the files after a few hours.
I decompiled a modified minecraft.jar with Optifine installed, and it seems it reworks a lot of the options menu code that the vanilla jar (furthermore, the FOV mod) uses. It would be a considerable amount work for me to figure out implementing a vanilla mod while accomodating Optifine's changes. As you could probably tell, I haven't had much time to get around to this. If I do, however, I'll try my best to find a fix if there is one.
Hm... is the hand issue going to be fixed? Is it going to be open source ever?
I can't open source the mod since it's just direct modifications to Mojang's code, and that's against the EULA iirc.
I mostly made this mod by comparing the FOV changes in Beta 1.8.1 to the code in 1.7.3 and added them accordingly. However, much of the code in 1.8.1 is still heavily deobfuscated (and many new decompilers can't deobfuscate the scrambled variables in the old beta code), so it's hard to track down the changes in the hand rendering code.
However, if anyone's still willing to give this a shot, I suspect changes need to be made in ItemRenderer or RenderPlayer that adapt to FOV changes.