RIA's offer this kind of custom constructed direct indexing as a value add, so there's clearly a market amongst the broader non-active-trader types.
I bet you could lean into the huge and growing ESG (
Environmental, Social, and Governance) sector, because people have very different opinions about what "good" and "bad" are. For example most ESG funds are heavily weighted to social media, but maybe you think oil and social media are both bad? There isn't an easy to access product for that.
Do you actually need currency conversions (in the sense that you deal in multiple currencies and want to normalize them to one) or do you just want to be able to use pounds vs dollars and have the numbers like reasonable for a UK person?
For sure we ultimately want to support the former, but worked on systems that do this, there's a fair amount of complexity depending on what you really need to do.
I'm the developer on Opstarts. I'm happy to answer any questions if anyone has them. I built it using Meteor, which has been really sweet to work with.