Hello Bill,
A solid timber mast could be a good way to go? They have many proponents for lots of good reasons. I would recommend that you track down your local one-man-band sawmiller, who (maybe like me) will have a Wood-Mizer mobile band-saw and the attitude to life that can get most things done with wood.. The mill needs a small extension, as they are 6.3m without it, but quite a few do. I would be happy to oblige but I think we may be a day's ride apart and the distance may make it a costly stick.
If you look on your favourite search engine for "mobile sawmill" followed by your county or location...
What I do with mine is to cut a beam of the length and outside square dimensions required and then fiddle about a good bit to get it tapered for the right distance and, for a big one, I can do the taper as well. It is important to choose a nice piece without big knots, of course, but the job works well. I did our own one at 42', (not a grown stick but made up out of 21/2" laminations) and a couple of others shorter, one of which was milled 8 sided and tapered, cut up the middle and glued back together again after being partially hollowed out.
Many on here would say that an ali tube, possibly with a wooden extension, is also a way of doing it. Streetlamp pole suppliers may not be too keen on selling you one for a mast, but if you gen up on what's needed on this site and make enquiries for a lamp post, not a boat mast, you might be able to use one of those?
Email me if you want any more help with finding a sawyer down your way.
Good luck!
Pol.