I've seen a few other packages leverage the thinkorswim API as an intraday data source. What's nice about them is that I was able to open a free account with free data just for depositing some money in an account (even though I mostly trade through IB).
I tried using DDE with the account but there is no backfill so it isn't that useful.
Tomasz, I know you have a lot on your plate and doing a DLL for them is probably not a priority. I don't know the technology behind a data DLL that well. Would it be possible for me or a small group of Amibroker users to hire someone to write a DLL to access their data just like the iqfeed works... or is it something that has to be done by someone inside of AmiBroker?