The system has a very clear API between GUI and backend, so future plans is to add more interfaces, a web based one is on the list (although IMHO web based interfaces are worse to use).
The LaTeX idea is great, so great that it's already done. I tried to keep the video short and don't show all features. I also have integration with mutt. Sending a new invoice is just a keystroke away and then mutt is opened with an attached pdf and a template mail body.
The account overview is the biggest weakness right now and something I look forwared to improve. I definitely take your suggestions with me towards that work.
Therefor my current solution is to have a really tiny presentation layer that is able to adjust to multiple UI.
If you write a blog post about the CRM and your experience in writing it, that would be a fun read.
Good luck!
I'm sure you're not the only one but I can see how this could be much nicer than a Web UI for someone (like me) who prefers Vim and Mutt over Atom and Gmail.
I have a supicision that OP is also a Vimmer who (like me) gets upset when a user interface doesn't accept hjkl and all the other idiomatic Unix/Vi keyboard commands.
Maybe you could automatically generate invoices with LaTeX and save a pdf, that would be cool.
Also, you could add an account overview, where you could see the balances of all your accounts, compare it with previous periods. Paint them red if you're expenses are soaring etc. Maybe some graphs...
You could also prepare a screen for financial indexes such as cash flow, debt-capital ratio etc.