Agreed. Distances less than 50 mi (80 km) should be easy. Go for it, but get the SL or SV with the more efficient heat pump.
I've only experienced maybe -10C to -15C. If you are below that temp, then you'll need to look at others for help. You will consume more electricity driving (I get 2-2.5 mi/kWh in winter but with the inefficient 2011 heater blasting) and get less kWh's out of the battery when cold, maybe as low as 15 kWh instead of 20 kWh in the warmer climates. So my absolute worst case is a range of about 30-40 mi (50-67 km) in winter with the heat blasting. Without heat, you should double that range. I've never had a problem due to my shorter commute and rarely see those temps anyway.
Now, that said, only using L1 could be problematic when really cold. Even if you're parked in a garage overnight (and I certainly hope so otherwise you're missing one of the best benefits of an EV), the L1 will only output 1.2 kW of heat into the cabin during pre-heating. It works fine for me, but I don't think the car has ever been below -5C in the garage. In really cold temps, the car may not prewarm all the way to 25 C, but it's certainly warmer than ambient.
Here's the biggest problem: Charging overnight with L1 (let's say for 12 hrs) will probably only get you 12 kWh into the battery. So if you get 2 mi/kWh when it's really cold, that's only 25 mi (40 km) of travel. Throw in a headwind both directions (yes it can happen), and you'll wonder "what was I thinking." Don't get me wrong, you'll probably do better, but you'll need to prepare for the worst and hope for the best. Personally, I would do it (and have done some crazy things: See signature line), but you have to decide whether you are willing and able to have back up plans on those extra cold days/weeks. If you go with L2 (16 amp or 30 amp at 240 V), then it's not a problem at all. Charge to 100% on those extra cold days and zoom on out.
The problem with L1 is that if you get behind on charge, it takes all day to catch up. For example, say on Monday you end up driving an extra 10-20 km for dinner or errands or don't get home until 10 pm. Then you only have 8 hr of charge time until you leave for work. Now you've only added 8 kWh into the battery, which might be only 15-20 mi of distance in the real cold. Are you willing to go without heat that day so that you can make it to work? It's not a problem if you have another car, a faster L2 EVSE, charging at work, or an emergency charger along the route (check http://www.plugshare.com" onclick="window.open(this.href);return false; to make sure). In your situation, it sounds like some of the back ups are missing. Not a good idea. Get the L2 and your feel better.
Edit: You'll have all summer to decide on whether you like the car enough to get L2.