Additions:
I think that using TCPDF would open up webERP to many other multi-byte character languages. I'd be very interested in seeing your code changes to effect the use of TCPDF as I am sure many others would too. If you could package up all the changes you made against the latest CVS and send to submissions@weberp.org it might be good to bring TCPDF into the main trunk of development and work through the remaining issues.