How about if you omit the initial '19' from the scriptPubKey:
$ clamd signrawtransaction $(clamd createrawtransaction '[{"txid":"71f2cbe9ff92b8c62a2bcfba5dfc9bc32a2d0c71bf55834e6d884b9ab0de201c","vout":69}]' '{"xK8vfFyKC4J2SHR2Hhk7whQAaCTGWbEEwW ":3.5}') '[{"txid":"71f2cbe9ff92b8c62a2bcfba5dfc9bc32a2d0c71bf55834e6d884b9ab0de201c","vout":69,"scriptPubKey":"1976a914c6580bcf8320c3ddaadebc9be9f38ac6fb59d21688ac"}]' '["Lo2RApGkaDZDePA347i56Lo4xRNGBwuxUgyQBC5cK9Ea2Kpn2mnt"]'
{
"hex" : "02000000b0da335a011c20deb09a4b886d4e8355bf710c2d2ac39bfc5dbacf2b2ac6b892ffe9cbf 2714500000000ffffffff018093dc14000000001976a91476d3380912c1dda6d575bdbac5348db0 e46d8c4e88ac0000000034706c6179206f7220696e766573742077697468206120312520686f757 3652065646765202d2d204a7573742d446963652e636f6d",
"complete" : true
}
$ clamd signrawtransaction $(clamd createrawtransaction '[{"txid":"71f2cbe9ff92b8c62a2bcfba5dfc9bc32a2d0c71bf55834e6d884b9ab0de201c","vout":69}]' '{"xK8vfFyKC4J2SHR2Hhk7whQAaCTGWbEEwW ":3.5}') '[{"txid":"71f2cbe9ff92b8c62a2bcfba5dfc9bc32a2d0c71bf55834e6d884b9ab0de201c","vout":69,"scriptPubKey":"76a914c6580bcf8320c3ddaadebc9be9f38ac6fb59d21688ac"}]' '["Lo2RApGkaDZDePA347i56Lo4xRNGBwuxUgyQBC5cK9Ea2Kpn2mnt"]'
{
"hex" : "02000000b3da335a011c20deb09a4b886d4e8355bf710c2d2ac39bfc5dbacf2b2ac6b892ffe9cbf 271450000006b483045022100acbe3ef8fd29e75c5043b5489c6b26b2e171387abb75d01be3445c 54499d1ff8022054ddaeeb932451bad74fa4dac2ff411a3a190fe8621d96f58b1873323d43e4be0 1210317219581a420e433f18a7d28b282cddd4e900f1a7efad35d54d8b881c3e67497ffffffff01 8093dc14000000001976a91476d3380912c1dda6d575bdbac5348db0e46d8c4e88ac00000000347 06c6179206f7220696e766573742077697468206120312520686f7573652065646765202d2d204a 7573742d446963652e636f6d",
"complete" : true
}
See how the 2nd output is longer than the first? I was giving the wrong scriptPubKey. I think the one I gave was trivially satisfied and didn't need signing.
Note that bitcoin core does much the same:
$ bitcoin-cli signrawtransaction $(bitcoin-cli createrawtransaction '[{"txid":"71f2cbe9ff92b8c62a2bcfba5dfc9bc32a2d0c71bf55834e6d884b9ab0de201c","vout":69}]' '{"15mx7Yjrb4xn5bBfvoEqNBXtKkN2zXHep7":3.5}') '[{"txid":"71f2cbe9ff92b8c62a2bcfba5dfc9bc32a2d0c71bf55834e6d884b9ab0de201c","vout":69,"scriptPubKey":"0288ac"}]' '["L2LQBARQyTS7m2aTraPsniiRRg5xB6tz3T3FJ2z3psQDKEMoRRZ7"]'
{
"hex": "02000000011c20deb09a4b886d4e8355bf710c2d2ac39bfc5dbacf2b2ac6b892ffe9cbf27145000 00000ffffffff018093dc14000000001976a9143460cfb610a0caad01f0a831424f3e47c583d058 88ac00000000",
"complete": true
}
$ bitcoin-cli signrawtransaction $(bitcoin-cli createrawtransaction '[{"txid":"71f2cbe9ff92b8c62a2bcfba5dfc9bc32a2d0c71bf55834e6d884b9ab0de201c","vout":69}]' '{"15mx7Yjrb4xn5bBfvoEqNBXtKkN2zXHep7":3.5}') '[{"txid":"71f2cbe9ff92b8c62a2bcfba5dfc9bc32a2d0c71bf55834e6d884b9ab0de201c","vout":69,"scriptPubKey":"76a91444d3d978157815376c1c5de25692531ee23c7f2088ac"}]' '["L2LQBARQyTS7m2aTraPsniiRRg5xB6tz3T3FJ2z3psQDKEMoRRZ7"]'
{
"hex": "02000000011c20deb09a4b886d4e8355bf710c2d2ac39bfc5dbacf2b2ac6b892ffe9cbf27145000 0006a47304402204327264dd9bbf5f1d2386b0b9e132c0840b2637c9d193f85674e491c9ad12773 022052305d35b933338de1bdb1175b80f585fd307ae6eed72224df070c78b6b177fa01210344785 787589e13c6e87d5ea3f20fc2ce30376d9a77282b170c78393bb37dfb5fffffffff018093dc1400 0000001976a9143460cfb610a0caad01f0a831424f3e47c583d05888ac00000000",
"complete": true
}