American Airlines allows mileage upgrades from any published coach fare to business class on international routes. This would save you some cash versus DL because you could buy the lower fares. The tradeoff is that AA requires more miles to upgrade (50,000 roundtrip), and its business class seats are not quite as comfortable as DL's. To my knowledge the only "free" international upgrades on AA require Executive Platinum status (100,000 miles or points per calendar year), and I believe this earns eight oneway upgrades.

dennis