Well, the module claims amps, but I find that around 300-350ma is about the limit, that's likely partially due to the size of my input filter caps. I have actually laid out another board with 680uf of capacitance instead of 300uf to increase the potential current output, but I haven't actually needed the additional capability yet.
Truthfully, I make these as small as possible as I am usually trying to cram them into something with wheels. 
For accessories, I'd buy one of the larger buck DC-DC modules and just tailor an add-on PCB with the AC/DC components. For higher currents, you'll likely want even more bulk capacitance, so there's no reason to limit the size based on this particular design.
