Many people ask me about how to affordably frame the bookshelf paintings and prints and I'm finally going to post about it instead of typing it out over and over; no idea why it took me this long to do so ;p
I like the Ideal Bookshelves best in white wood frames, and the best off-the-shelf ones I've found are West Elm's gallery frames., and I also like IKEA's Ribba frames. They both come in black and silver, in case the white is not for you. They have great rectangular ones in various sizes, and even nice square ones that often fit the paintings with fewer books (7 or so) perfectly.
Unfortunately, the mats that come with the frames usually have too small an opening for the bookshelf images (especially for the West Elm ones; the IKEA ones are more straightforward). But you can get a custom white mat cut for you at most art supply and framing stores; it usually costs $10-15 at most. Some places may even just cut the opening on the West Elm mat larger for you, to fit the image.
I've updated the Ideal Bookshelf "gift package," so to speak. Now, if you want to give a certificate for a custom painting as a gift so that the recipient(s) can pick their books later on, I'll mail you a card with the info on it, plus a postcard to show an example, all in a nice envelope. You can then write inside the card and give or send it to your friend.
If it's very last minute then I can still email you a PDF version of the card, no problem.
Also, if you proved me with the recipient's email address and the date of the gift-giving event, I'll email them a reminder a few weeks later, to make sure they send me their books. This seems to be especially useful for wedding presents, so that the couple has time to honeymoon and then settle down before working to compromise on their combined all time favorites ;)