For me, one of the N900 worst drawbacks is the lack of a useful, complete and "finger friendly" Scientific calculator. One that could be closer to that was S&C calculator, but it didn't worked fine, () were useless and didn't obbey op. hierarchy. The "CalculateIt" also lacks some things as (), and it something like RPN but it's incomplete, as you can't really control your operations and finishes doing arbitrary calculations.
x48 is also RPN and well working calculator, but just like ATI85, buttons are too little and you take a lot to type what you want, and they are slower than a "native" calculator (not emulated). Sometimes, Specially ATI85, is the best approach for a descent scientific Calculator in N900.

Less "Finger Friendly", and with a broken UI is Qalculate!, but until now, It's the most powerful calculation tool I've found on N900, as using Keyboard, it's the most practical for long and complex calculations, but can't do the trick for "quick" things (not finger usable) and The broken UI is desperating at times.

So, SpeedCrunch is very similar to Qalculate!, but still some "details" make it less usable, like colors in the input box (shouldn't "highlight" the entry, it just decreases contrast), "function" list not displaying very nice (It would really be better if there was a button for displaying that list like a pop-up menu), and the Buttons should admit at least one of these:
-Choose a predefined layout (trig. fn, hyp fn, stat and prob. fn, basic, generic scientific, logic and programming, etc)
-Be customizable (possibility to choose which buttons you have available)
-Parenthesis, E (x10^), and ARROWS (At least left & right, this would be great)

Thank you for re-taking the project, I would like to see this calculator a little more useful in maemo, and I'm sorry I don't know about C++ or QT, I can just give you my "ideas".

Would it be worth to start a new calculator, maybe based on SpeedCrunch code, but with a completely new UI with characteristics described before? Would it be possible?