I've checked on Manx macaronics. The only two I've come across are poems, one by William Kennish and one by Tom Shimmin. William Kennish wrote The Manxman's Farewell, which started like this:

A Manninagh dooie, from the clean I was troggit Close by the foot of the bridge of Cornaa Whose keystone was fix'd in the year I was ruggit Three miles and a half from the town of Rhumsaa.

A true Manxman, from the cradle I was raised . . .

Whose keystone was fix'd in the year I was born . . .

The Cornaa/Corrany/Corony Bridge was finished in l799. I don't know if this is the only part of the poem which is a macaronic, as I don't have a copy to hand. The rest of his output was in English about Mann, and not without folkloric and historic interest.

As a matter of interest, at the New York banquet to celebrate the opening of the Panama Canal, Ferdinand de Lesseps praised William Kennish as the man who had discovered the only possible route to join the Atlantic and Pacific without using locks. This would have been via two navigable rivers in Ecuador which he proposed to join by means of a 3 mile tunnel through the Cordillera mountains. Kennish was also an inventor who came up with a number of things used for many years by the Royal Navy.

Anyway, that's William Kennish from the north of the Island. Tom Shimmin, from the south, was known as Tom the Dipper. He was something of a rag gatherer, but also a bit light-fingered. There was a story of how Tom was delivering some sort of sermon, and he got the people to look up to heaven. While they were looking up, he slipped a block of cheese under his coat. On another occasion, a shopkeeper saw him slip a pound of butter into his cap. So he invited Tom into the back room for a cup of tea in front of the fire. The shopkeeper amused himself watching Tom getting agitated, and going out with a cap into which all the butter had melted. At the age of 78 he built his Cottage in the Heather to live with his wife up in the hills.

Tom the Dipper was a writer of doggerel, but he produced one macaronic. There are quatrains. This is already rather long, but if you're interested, I'll copy that for you as well.

Mish, lesh firrinys,

Bobby Bob