Apart from that, the multibyte issue seems like the big one. Any way around that?
Conversion of pg_wchar to multibyte character is the only way I found to avoid serious hacking of existing regexp code. Do you think additional function in pg_wchar_tbl which converts pg_wchar back to multibyte character is possible solution?
Do you have any notes on it? I could make the patch which adds such function into core.