I hear that getting a marriage visa in Bangkok requires proof of 400k or so and there are agencies who'll lend it to you for 30k. That's about the cost of a flight to the UK where the northern consulate don't ask for proof.

Does anyone know how fussy the embassy in Jakarta are for proof of the funds to support oneself?

You don't get a "marriage visa" in Bangkok, you would get a one year "Extension of Stay", financial requirements are 400K in a bank account or a monthly income of 40K. I think KL will issue a one year multi-entry Non-Immigrant "O" Visa wih 100K in the bank, other Consulates may issue a single entry without.

Here is one report from Jakarta found in the Pinned Topics Section.

http://www.thaivisa.com/forum/topic/426687-jarkarta-multi-non-imm-o-m/page__p__4092921#entry4092921

Cheers