Awkward verbs: to rota

A while back I blogged about how 'pro rata' makes an awkward verb as there seems to be no consensus on how the past participle should be written.

I've just thought of another, similar-sounding verb that poses the same problem: 'rota'. Although the Concise OED lists 'rota' as a noun only ("Chiefly Brit. A list showing times and names for people to take their turn to undertake certain duties"), I have heard it used as a verb to mean something along the lines of 'to put into a rota'.

And no, I'm not imagining it: after quite some searching I managed to find a Personnel Today question-and-answer page in which a respondent ('BKay') writes:

Because we work a 7 day week if anyone is rotad to work a b/hol they get the day back in lieu

This writer has chosen 'rotad' as the past participle of 'rota' but I can see arguments for 'rotaed' or even 'rota'd'. What do you reckon?

And are there any other English verbs out there (apart from 'pro rata' and 'rota') whose spelling ends in a consonant and then the letter 'a'?

Pro rata, pro ratad, prorate

One of our members of editorial staff wanted to use the adjective 'pro rata' as a verb, and asked the subs' desk how the past participle should be spelt. As far as I could see, there were three contenders:

• pro ratad
• pro rata'd
• pro rataed

I considered them all, but they all seemed ugly and potentially jarring, so I advised the staff member to recast the sentence: for example, instead of writing 'the company pro ratad the salary', she should write 'the company paid the salary pro rata' (or, '...on a pro rata basis'). However is this a sufficient reason not to verb something – because it looks 'ugly' when written down?

And what would I have done had 'pro ratad' been used as a verb in a direct quote?

NB I see in my Oxford English Dictionary that there is a verb 'prorate': "allocate or assess pro rata". However this isn't in common use this side of the Atlantic, as the OED recognises, so isn't much of an option. But it would be a very useful verb to have...