Been discused recently, but trying to summarize what I think is state of things...
-equinox 3d, good spline based modeller for linux, I think recently got some kind of support of lightmaps.
-In Blender, You can bake radiosity(not only radiosity, i think), and all, even you can also bump and normal maps in Blender using the following script (new since the latest post I have from this here) (oh, you need Blender 2.37 at least, that is, probably the actual oficial one (2.37a, though it was said to work with 2.37, surely works with oficial 2.37a)) :
http://www.alienhelpdesk.com/index.php?id=22
That little wonder is something I haven't tested...Why ?
Well, having LMMaker free now, purchased Giles, learnt the hard way to use FSRAD and MIM/OCT tools, I have little to no need to use more, besides now I'm not in the midst of any level editing project...
But if I had the time, I'd test that one. Maybe is the solution.
Now, being only in Linux...I doubt you could use the DOS proggie OBJ2MIM...if you could, it'd be a matter of just exporting an OBJ out of blender to which you asigned the baked uv texture as texture. You'd have a previous copy of the model with other UVs than the generated by the blender raybaker script, and its texture. You give em both objs to obj2mim, it outputs a mim file, use the MIM loader to load in irrlicht.
In worst case, you can just render huge textured with lighting baked: ie : a whole one for a whole wall, another for the floor, etc. All smashed into uv channel 1 (the only one you have in Blender, actually)