The roofs/rooves question may date back to Old English. The OE f was voiced when it came between two vowels. If the plural ended in an es then rooves would be correct; if it did something else (ICLIU) and the s plural was coined later in, say, Middle English times, roofs may well be proper.

I have also heard beeves as the plural of beef referring to beef cattle on the hoof. This usage obviously cannot predate Middle English so it would be by analogy to earlier forms.