3DS firmware 7.2.0-17 has released for a few weeks. All most all the flashcarts can works on 3DS 7.2.0-17. Guys, I will recommend a reliable r4i flashcart site. http://3ds-flashcard.com I have bought 12 r4i cards from this sites. Some for my friends. Fast shipping and better services. I like this site. 3ds-flashcard.com is the top1 flashcart reseller.
the best r4isdch card far as i knew was r4isdhc rts 3ds,it came from old r4 team,with a regular updating and top game compatibility. 7.2.0-17 update didnt block any flash kit,so r4isdhc rts can directly work on it.If you need,here is a usa based store for you : http://www.modchipfactory.com/r4isdhc-rts-3ds-flashcart-for-3ds-xl-3ds-dsi-dslite-p-8.html
Make sure you get the right kind. From what I've read, the supercard dstwo is the best flashcard for the latest 7.2.0-17 system, I bought my supercard dstwo from http://www.r4flashcart.com/10-supercard-dstwo-flashcart-for-3ds-xl-3ds-dsi-ds-lite.html and the kernel is updated all the time by the manufacturer.