Thanks for the response, Jeffrey. Your suggestion (Format > Lists > Insert Bulleted Lists) is helpful, but I was trying not to simply use the toolbar icon, not hover the mouse up high until the system menu bar appears.
HOWEVER, I did find the solution. If you customize your message toolbar to show lists, you MUST move the icon to the right side of the menu bar. If you leave it on the left, it gets repalced by the "send / cancel" buttons. Odd that mail doesn't know to shift the list button over to the right, but there you have it.
FYI, this is true for most buttons...if you customize your message menu bar, but leave the options on the left, they will be replaced by the Send / Cancel buttons when in full-screen mode.