The latest version on the site is XL_Engine_Release_02 and the executable inside the zip archive is dated 6/17/2011.
Here is what the page says:
* DarkXL is highly playable and mostly complete but it is still an Alpha Build. You may experience crashes or be unable to finish the game.
* This version of DaggerXL is an older version and is very incomplete. You have combat, loot, dungeons and can explore the various cities and other locations. However NPCs, quests, guilds and other game functionality were still not implemented as of this version. However I am currently working on the Beta release that will make the game fully playable. If you download this version be prepared for missing features and bugs.
The first XL Engine release is now available. Contained is DarkXL Build 9.50 and DaggerXL version 0.199:
Download here: XL Engine Release R2
DirectX End-User Runtime Web Installer
I don't have Daggerfall or Blood so I can't comment on the progress of those games (and I haven't played Outlaws since LucasArts released the last official XP patch many years ago). I played through Dark Forces in DarkXL and I thought it was great. It felt pretty awesome playing it. It wasn't 100% but pretty close to the original game and looked great, comparable to upgrading the original "Doom" from DOS into 3d-accelerated windows (ZdoomGL, doomesday, etc).
The only thing that really was goofed up was in the later levels when you face the Dark Troopers. Some of them are just standing there like cardboard cutouts. The Final Boss is super, duper easy... pushover easy. And the final door didn't open for me, so I had to cheat to "win." So it was pretty unsatisfying there, but otherwise a very worthy effort.
The official website (and the "blog" where news is posted) was last updated a few weeks ago (Nov 10, 2013) and the latest updates have been about DaggerXL.
On the forum I saw this:
Post subject: Happy Holidays
PostPosted: Thu Nov 28, 2013 3:17 pm
XL Engine Developer / Site Admin
Joined: Thu Apr 14, 2011 4:05 pm
I haven't been posting updates in the last few weeks, preparing for the holidays and other personal matters. However I will be posting updates again starting next week (and maybe sooner as time permits).
So Happy Thanksgiving to those that celebrate it.
I don't know how many years it will take to finish or even if it will be finished (DaggerFall probably will take the longest) but I wish Lucius luck!