I don't have a removable storage device that has over 40gb of space on it, but I do however have a cable to connect my PS3 to my computer by USB. I was wondering if I could say... make a partition on my hard drive that would act as a removable storage device for the PS3.
There are ways where you can partition a drive of your HDD to have the same partition as those external flash and hdd devices, but I don't think that the partition would initialize when you connect your pc to ps3 via usb.
The USB system is designed to have 1Master and upto 127 slaves in one bus.. What you are talking about is connecting 2 masters to each other in the same bus. This is not possible without 2 things. Hardware or Software access.
1) hardware access (would require you to modify your PS3 and add a slave USB connection. And add support in PS3 os for slave usb to work.
2) OS access and modification of PS3 USBHOST/USBHOSTFS and a couple of more driver modification to work as slave instead of master ..
So no.. it wont work the way you are asking. The best easiest and most noob friendly way is to use an external hdd for transfering stuff.
With the right adapter (Available at ya local PC shop) you can plug a normal desktop size sata drive straight into your ps3 so i dont see why you wouldn't be able to do it the other way around then you can shop for a cheap 300GB.