Tá ceist agam, ma's é do thoil é:

“Seo Tomás.”

Nó

“Seo é Tomás.”

Which phrase has more currency?

It seems like these sentences have no verb- is that correct? It is that unusual?

Gan bhriathar, go deimhin agus cén dochar. No verb indeed and no harm done. The person / thing is visibly, or in some way subjectively, present.

Both have currency, the frequency might be confirmed with a corpus search.

Rinne mé cuardach beag ar ball ar Thobar na Gaedhilge http://www.smo.uhi.ac.uk/~oduibhin/tobar/ de chuid Chiaráin Uí Dhuibhín ag ransú 'Seo an' agus 'Is é seo an', i ndiaidh a chéile. Tá foirmeacha na copaile ('Is é seo an...') níos líonmhaire de bheagán ar an leagan eile 'Seo é an... '
Forms with the copula ('Is é seo an ..') are more frequent than forms with the bare 'seo é ....'
(Ba é Séamas Mac /Ó Grianna an t-údar ba mhó líon abairtí sa ransú.)

'Graiméar na Gaedhilge' (no date, donkey's yrs!) regards the latter, 'seo é...' as a contraction 'in the spoken language' of the Copular usage, but it may be best to just consider it a verbless logical phrase.

Go raibh maith agat!

Tá fáilte romhat a Jim.

I found another example of this, I think,

from the "Irsih Echo" newspaper, 1/14/04:

"Fear glic é Ó Mealláin."

A wild specualative thought occured to me: I wonder if this contraction might be the result of the Norman influence, in that "é" sounds like "est" in French n'est pas? Perhaps softening the verbal dissonance that a missing verb might usually present.

Is diabhalta an smaoineamh é a Jim.

You're putting me thinking now Jim, but oíche Dé hAoine, ba mhaith súil a chaitheamh ar chúl an tí féachaint ar leagadh mála guail ann dom! Friday night, you'll forgve my darting out of the office! It's really some thought however, going from verb to pronoun. Is fánach an áit a bhfaighfeá gliomach - you can pick up little jewels in the strangest of places - so keep tickling at this in the future. It is an attractive possibility.

A very generous assessment, go raibh maith agat!