We have a block with 7ktxns in testnet
https://www.blocktrail.com/tBTC/block/0000000000001280a3d758cb956e565daffd5af0e6b6723f28e1cbcda0da8652and block size above 2.6mb
▶ btcctl --testnet getblock 0000000000000aefc03aefe53098b095cb41c93a91eabe7a494a36e4fa0c7cd0 | more
{
"hash": "0000000000000aefc03aefe53098b095cb41c93a91eabe7a494a36e4fa0c7cd0",
"confirmations": 3,
"strippedsize": 27485,
"size": 2767517,
"cost": 2849972,
"height": 893443,
"version": 536870912,
"merkleroot": "d33fe22bedbb078215c57a451756f602db1db559b101f230964e3ece7da6b0e9",