Contact this wholeseller and ask where you can buy the larger specimen. They are usually very happy to let you know because it means their stock will be moving...if a little further down the line.
Call them.
Cheers,
McPeg

Find a retail outlet that sells Iseli products.
The rep for Quebec is:
Jean-Francios Devoyault
Au Jardin de Jean-Pierre Quebec, New Brunswick,
Newfoundland, Nova Scotia, Canada
Business 819-858-2142, Fax 819-858-2783

Yes, actually I have a bunch of stuff on order from J-F already.
But I wish Iseli would at least post the available plant sizes on their web site (preferably with a matching "suggested retail price")
Anyway, I thought it might not be a bad idea to try to find a Canadian source, in this particular case.
McPeg's suggestion to contact the wholesaler is a good one, unfortunately now I've lost my link to where I found the P. bungeana, and Google won't find it again....

Our grand mature 25-plus foot tall, multi-trunk Lacebark Pine (one of 2) fell victim to heavy snows the winter before last. Does anyone know where we can obtain either a replacement or a younger tree? So far I have found nothing. Our second tree, equally tall and likewide-shaped lost about one-third of itself in the same storm, but still lives...so far. We are in NJ, USA. Thank you

Wow !! .....there's an old thread come back to life !

I think that availability is somewhat improved since 2006.

Certainly it should be easier to get in the US than in Canada.
One way is to order from an Iseli distributor in your area -- see link below....

Good luck !

Here is a link that might be useful: Iseli - Lacebark Pine