You said you do have access to a linux box over lan, why not set up an ftp server on this box and do an installation via ftp? SuSE does have such an option and I'm quite sure RH must have something similar. At least this was the easiest solution for me when I had a similar problem.
You really seem to have quite an issue with starting an installation environment though... I don't see any way to do this without any floppy- or cd-drive. Maybe there is a way of booting over the lan but I can't think of one...
That doesn't mean there is none, some guru can surely help you with that!