All in title.
I am wondering if there is any alt-coin with 8mb block-size limit that we can run tests on ,
to get some ideas about what we are running to if we increase the block-size limit in bitcoin .
This is a silly question because there's no reason for any altcoin to have blocks even 1/10th the size of bitcoin. Take litecoin for example. Many blocks, if not most blocks have zero transactions other than the coinbase. Block sizes are 2-10KB. LTC has <1% the number of transactions /min of BTC. LTC could have 100MB blocks and it would make no difference - there's not enough volume of transactions to come close to filling blocks whether large or small.
I believe, but not 100%, Litecoin has a 4mb block size currently.
It was originally programmed that way, not implemented later.
Edit: But yes, Litecoin's daily txs combined are not even more than 200kb.