I'm going to rephrase this. I'm not implying it might explode. This isn't a careless suggestion, you should always test Li ion systems with full caution if you set up a new one. Saying this doesn't mean I think it will go wrong, you just have to be rigorous.
So you can't just use a lower current, with a higher resistance. And using 3.6V isn't going to put any significant charge to a 3.7V cell. I suggested 3.8V in my post, because that will. The voltage will closely approach the 3.8V value and never reach the normal 4.2V upper limit used in most fast chargers (note, those switch off the charge at that point). That means you can leave it connected indefinitely. It might be best to use a current limit resistor to limit initial charging current to 400 mA, but with the small difference between cell voltage and 3.8V you might not need one. It won't be a fast charger but it will be a safe one. But that upper voltage is critical. You might improve performance with careful adjustment to 3.9V, but it must be strictly controlled, and never reach the full 4.2V unless your charger has an auto-switchoff if it gets there (either that or strict current limiter). I think using an LM317 regulator is best, because it's far easier to set a safe value than to try to 'economise' with a simple zener circuit. And if you wire it with an adjustable pot, make sure the Adj pin goes LOW, if the pot wiper fails, not high or open circuit, otherwise the regulator output voltage will go high.
EDIT:
http://www.batteryuniversity.com/partone-12.htm
That confirms a strict limit of 4.0V (4.05), stating that trickle charging causes risk to safety by plating metallic lithium if the voltage exceeds this. I suggest 3.8V to leave a margin, as temperature affects this. That page says 3.8V lets you get around 50% charge, but that's good, it's close to the 40% for nominal best storage life. Anyway, this is about the only way I'd consider leaving a Li-ion battery on a constant maintenance charge.