The short answer is yes I think it would be possible. You would have to spend some time working out file formats and some programming though.

I think if I was to try to approch this as a Windows user, I'd try to find a plain text version, the one John in Brisbane has been working on with the tunes in abc would probably be ideal... I'd probably sling it all in a database. Relibably getting the right data in the right fields may be difficult but if you could achieve that, at least with an abc version, it would be easy to produce a fast searchable sytem which would allow you to add songs and also produces quality output.

My own attempt at such a system (not the dt but the dt would be no more difficult) is here With the data organised, it should be a no brainer to convert something like that into something that would run locally on a mac if you were prepared to install some software.

You could also look into using something like MS access (I think there is a Mac version) to build a user friendly interface.

With a Mac. If you could find an abc copy, Barfly would also be worth a try. That would let you read the text and on abc portions, display and play the tunes for you. I'm not sure how searching for the songs would work out.

Anyway, a few suggestions for you...

I do agree with the thoughts on sharing the songs BTW but I can see reasons for people wanting to do what you suggested.