Checking before getting a first OpenWRT device with extra storage

Hi. I am contemplating buying some hardware for OpenWRT, which I have never used before. I have some idea of what to do, but I thought I should check first. Especially since I'll want to buy two of whatever I choose, so that I have a backup.

My internet speed is 6Mbps, and I'm one person. I do intend to use my device as a bastion that runs a few lightweight servers such as e-mail. I do not expect anything to need significant CPU or RAM, but I do need a few gigs of persistent storage.

At one point I had my eye on the Carambola - a small and cheap two-ethernet-port computer that can be bought with a case. However, it has since dropped off the recommended list (for want of more RAM), and I would have to dedicate its one USB port to extra storage. While it has several big brothers, for some reason none of them are offered in a box.

I'm currently thinking about the Banana Pi R1. It looks a little overpowered and thus pricey, but the cool thing is that there's space reserved on the circuit board for a full-on 2.5" SATA device. Cases have to be ordered from different sources than the computer itself, but at least they exist.

I'd summarize my budget as: I feel like the BPR1 is a splurge, but I'm willing to make that splurge.