Why don't I have a custom title by now?!
ZDCMP1 has over 29K linedefs, and ZDCMP2 has over 77K linedefs.
ED4RFO has 10K in MAP08, 15K in MAP09, 20K in MAP10, 17K in MAP11, 19K in MAP12, 17K in MAP13, and 32K in MAP29.
Hellcore 2 MAP10 has 15K linedefs, MAP11 has 12K, MAP09: 11K, MAP03: 10K, MAP05: 11K, MAP01: 17K, MAP12: 15K, MAP04: 18K, MAP02: 17K. (MAP06 and MAP08 are the only ones under the 10K bar.)
KDIZD is over 10 for all its maps*. M1: 17K, M2: 16K, M3: 34K, M5: 35K, M6: 34K, M7: 26K, M8: 29K, M9: 24K, M10: 34K. (* Not counting TITLEMAP, INTERMAP, and CREDITS since they aren't normal, playable maps.)
Most of the maps used by Graf's benchmarks should be well above the 10K value.