Try your local gesneriad society (African Violets etc). I have read that it is very hard to keep going away from its natural site. I have one which "volunteered" in a pot with other north qld sourced plants- must have been a seed in the soil mix. Over 4 years it has not set seed and only flowered once.

I ran across this old post when doing a search on "boea" and, despite the age of the post, I thought I'd comment on my Queensland Rock Violet experiences over the past few years.
About a year after this request was originally posted, I too was searching for this plant and was coming up empty handed... no nurseries had them in stock, etc. Then, a kindly gardener at the Mt. Annan Botanic Gardens offered to give me some old plants he had in his greenhouse.
For the first year or so, these plants declined no matter what I did... and I made a mistake or two that almost killed them off. Then, half in desperation, I tried a new soil mixture of my own invention... filled with sphagnum and peat... and the plants loved it and have been thriving ever since.
They do well in several different locations in the house and in the garden and heavily flower through the summer. This plant is a joy and pride of mine now and I wish more people knew and grew it... especially here in Oz.
I might attach photos and details about my plants... but, due to my busy-ness, that probably won't be for awhile. In the meantime, I'm more than happy to chat to anyone interested in this plant... and, if you're in the Sydney area, you're more than welcome to pop around and see them for yourself... and take a leaf or two to start your own plants, if you want.

I finally got around to posting details of my experience with Queensland Rock Violets and a photo of one of my plants... follow the link given below. If anyone wants to see more Rock Violet photos or wants to chat more about Rock Violets, just contact me.

Here is a link that might be useful: More on Queensland Rock Violet