It is common practice for framers to combine two or more mouldings together to create new profiles, shapes, and styles. This can be very good for replicating some older frame styles, using easily available shapes and without the expense of having profiles custom made, especially if you can modify the mouldings with a router or table saw. I think this method works best when you use barewood mouldings and are going to do some sort of hand finishing on the frames, be it paint, gesso, or gilding.
Using the method with prefinished mouldings can look as if you have just stuck different frames together, as the finishes may not match up that well, although there are exceptions where it can work very well.
The simplest example I do all the time is just a inner scoop, bevel, or flat shaped moulding used as a wide slip with an outer frame, these are glued together and then gessoed and finished as one frame. You can create some wide and stunning looking frames simply by adding a number of mouldings together. The photos above are basic examples and all modern looking, I will post some more traditional and complex examples sometime soon.
