I couldn't open that "wish.com" link. It required a signup/login. Newegg has good deals on flash drives though, many with free shipping.
For anyone curious. I did some more testing. I tried a 32 Gb, fat32 formatted micro-SD card in a USB adapter, and it worked fine. I assume a 32 Gb flash drive would work the same. Then I connected a 1 Tb Seagate Backup Plus USB-3 external drive, formatted with NTFS. It worked too, powered by the Obi, no problem. The Obi200 USB port only supports USB-2 but the drive is USB-2 compatible. It's not speedy though. I downloaded a 500 Mb file and it took about 140 seconds, within my local wired network. Painfully slow. I transferred the same file directly from the drive to my old XP computer through a USB-2 port in 17 seconds.
I did one other test, just for completeness. I plugged the microSD/USB drive into an unpowered 4 port USB hub and plugged the hub into the Obi USB port. It worked. I knew it would but it was easy to test it. The Obi20x USB port does support multiple devices, with a hub. I think that's even documented somewhere. Overall, the Obi firmware team have really done a lot with the USB port. Bluetooth, wifi, file sharing, and external FXO, and all at the same time. Still room for improvement, but credit where it's due. It is impressive. If they could support bluetooth headsets, manage Samba file sharing, and support auto-failover on the FXO port, I'd be even more impressed.
So the remaining question is whether the exFat file system which is used on >32 Gb flash drives, is supported. And for curiosity, if any linux file system is supported, but that's beyond my needs. Probably if I reformat the flash drive to NTFS, any size would work, but I'm still hoping someone has tried this and has the answer. Somebody out there must have an Obi20x and a yuuuge flash drive. It would be nice if Obihai would publish specs for this.
AS for multiple partitions, I suspect only one partition would be seen by the Obi. I did plug in a 2 Gb Sandisk Cruzer flash drive which has a U3 system partition and a data partition. The data partition was recognized but there was no sign of the U3 partition, which mimics a CDROM disk. (Windows assigns the first available drive letter to the U3 partition, as a CDROM, so I guess it's first on the flash drive. The main fat32 partition gets the next drive letter.) Judging from the Obi200 interface, I very much doubt that an Obi will work with more than the first FAT or NTFS partition on any drive.