Does 意大利 ever get read as 意太利? I have heard 意大利 read 意太利, as a sort of half-joke half-honest pronunciation. This is funny because some dialects do read 大 as /t‘ai/ (think: Gan, Hakka, Min Nan, etc.).
《现代汉语方言音库 • 成都话音档》also has an entry showing:

大 t‘ai⁵³ (白读音) 又ta²¹³

Some compound words with 大 can even be read /t‘ai/.
It dawned on me, though, that the /t‘/ pronunciation does seem to match the Western pronunciation of Italy much closer than, what we might call, the initial D sound (/t/) in 大.
It's true, this could be another Holmes (福尔摩斯) translation - transliteration via topolect. I haven't been able to find much information on the Chinese origin of the word Italy though.
Does 意大利 ever get read as 意太利?
Yes. And sometimes, for an ironic/sarcastic vibe (not necessarily negative) and under a very informal situation, people would write 意呆利/意呆梨. As the transliteration comes mainly from English，where in the Italy the æ vowel doesn't exist in Chinese pronunciation, and 太 seems to be closer to the English word Italy.
And again, in formal, even the slightest sense, it is only correct and proper to use 意大利。