Can I configure Bitcoin (Linux) with a custom wallet location? The default setup on Linux/Ubuntu has Bitcoin storing the data in the ~/.bitcoin folder, which is usually not encrypted with TrueCrypt.

Suppose I do now want to rely on the internal Bitcoin encryption system, but instead want to save the wallet to disk on using TrueCrypt encryption. Currently, I have a separate TrueCrypt data file, that I mount to a partition, copy files from it to ~/.bitcoin, and when I'm finished, I copy the files back to the truecrypt volume, and shred+delete the copies on ~/.bitcoin.

This is bothersome and error prone.

Can I configure Bitcoin to only take the wallet from /media/trucrypt, but keep the blockchain data in ~/.bitcoin?
The bitcoin startup argument -datadir=&lt;dir&gt; allows you to specify a data directory, including the wallet file. 

That'll still require you to pass a custom argument I'm afraid. The config file is also in the data dir, hence there's a chicken-and-the-egg problem that makes it impossible to configure up ahead. Unless you're savvy enough to change the default constant in the source and recompile, which might be okay since you're already running Linux.