Although the tmpfs answer would usually work (thanks Ignacio), however, in my unique case I was looking for something a little bit more specific.
I found information about how to configure ramdisks from this link
Linux Ramdisk mini-HOWTO
unfortunately, this link is broken, but if you google the url, you can view google's cached version of the page. Also I learned about kernel configuration options from this link
Linux Kernel Documentation/blockdev/ramdisk.txt
There are two kernel configuration options that you can set in your .config file:
This configured my kernel to create one ramdisk that is 10G at boot time. Please note that the size is specified in KB and don't specify more memory than you actually have. (If you are editing your .config with make menuconfig look under Device Drivers->Block Devices)
Also, like I mentioned in the question you can specify the size of the ramdisks you create via the kernel boot parameter
ramdisk_size. So I currently boot my machine with the line:
kernel /vmlinuz-220.127.116.11 ro root=LABEL=/ rhgb quiet ramdisk_size=10485760
Now I can boot my machine and I can make a filesystem on it, mount it and use it exactly like a block device.
# mkfs.xfs /dev/ram0
# mount /dev/ram0 /mnt/ramdisk