Let's give it a go then...

[GoldenArrow]

Runner. Mid 20's. Ex national standard 400m. Now wants to run 10,000.

Current time: 37 mins
Target time: 30 mins

Wants to use weights to improve performance. Doesn't want to add too much useless mass.

Weight/Cardio training thoughts?

[PikeKing]

need more info, whats his weakness? whats his finish like? what are his strong points?

[Robert]

Running the 10k he ain't gonna put on any useless mass even if he wanted to. IMO:

Use lower strain stuff: 70% for sinlges and doubles. Not enough to have any serious impact on his running but enough to illicit strength adaptation?