Here is a short description how to play, I guess, any of the mods that we can find in the installation directory of the Half-Life beta:
First some info about paths: I have steam installing everything to ~/Steam and my Half-Life beta installs in ~/Steam/SteamApps/common/Half-Life
When taking a look at this Half-Life directory it can be noticed we see some familiar names (or at least familiar to those who like to play around with the Half-Life engine before). For instance the folder cstrike hold the libraries for Counter Strike, after seeing that I took a gamble and went to complete my own set of files for Day of Defeat.
What I did: Make a copy of the Half-Life directory called Day of Defeat. Then I proceeded to download HLLib from http://nemesis.thewavelength.net/index.php?p=35
and used this to extract the GCF file for Day of Defeat that I had available in a wineprefix I used for steam before. I used the command `wine HLExtract.exe -p day\ of\ defeat.gcf -e root -d ./ex` to extract the GCF to a directory called 'ex' then I copied the files from this directory to the 'dod' subdirectory of my 'Day of Defeat' directory.
Next start hl_linux with parameter -game dod to launch Day of Defeat.
I expect this approach to work for any of the other Valve mods of which we can find directories with the client libraries in the Half-Life beta.