No, not simple if you actually mean you wish to stick with the wagon design plus more size than an F31 has. Keeping in mind that the F31 is noticeably larger than the E91 was, which I had for a couple years, and it was really quite spacious for the tight handling it provided. The E61 does not even come close in terms of the sports car-like handling the E91 provided with the sport suspension and staggered 19" wheels. It was a manual of course

If you're fine with a large wagon, then you must either buy from broader used choices or limited new options.

The closest thing right now to the E61 is the Mercedes E350 with similar factory power and fuel economy. If you have the funds, the newest AMG is all wheel drive too and will blow the doors off our E61 even just in terms of handling. Massaging ventilated seats sure sound nice to me.

 

I went in to size fit the new 3 and the cabin room is very good for 4 (much better than the old E90/E91 which I looked at in the past pre E61 purchase). Where the F31 falls apart is in the cargo area. I wasn't expecting E61 size but I was excepting more. I am in the early stages of E61 replacement and being a consumer this is the time to look at all options (minus SUVs of course). If BMW N.A. did offer up the F11 it would have been a no brainer.

The E350 is a possibility but that model is due for a major overhaul in 2016 therefore there is no point looking at a 2015. Question is, will Merc offer a wagon in N.A.?

 

Panamera: large enough in the hatch area or not? Very sporty obviously. Possibly a manual in v6 build because the Cayenne is available with a manual/v6 which was pretty cool. I drove the newer one and the driving enjoyment level was high.

E350: reason to wait in my opinion is in case the diesel version becomes available in North America.

What kind of cargo area shape do you need? If it's not the height of a wagon shape, then large sedans actually have more space sometimes like BMW 7 and Audi 8.

Why so against the "suv"? These days there are some that out handle your E61 or at least provide similar handling. The BMW x5 35d is quite nice and would be an easy transition for a long time BMW driver. It would also get better fuel economy than E61 while providing ample cargo area.

Similar choices are the Cayenne or Q7 but the Q7 feels larger than it is while the BMW feels smaller than it is. Some of these "suv" types are really just "tall cars" anyway. If you would consider my LR3 to be an SUV, then those above are just cars with higher roofs. Due to my LR3 boxed frame some owners like to call them "trucks" but to me trucks are bigger and more heavy duty built. Thus LR3 = SUV, X5 = car.

Diesel ML would be ok but I've heard more people really enjoying the Q7 tdi, which by the way is what I think you should go drive, that an the newer X5 35d. As you may be aware, both of those, including the Cayenne tdi, handle much nicer when equipped with higher spec suspension options.
Porsche: pasm and pdcc are incredible
X5: sport/dynamic, whatever it's called
Q7: air suspension and similar upgrades

For travel, unless you are in a true sports car, these small suv's above really are as nice to drive but provide better view of the landscape and deal better with deep snow or rutted forest roads.

You could just keep the E61 and in a while just add the larger touring vehicle.

 

What about importing an F11? Or is that impossible? You can even go to germany and pick it up in the factory yourself, and drive it to the boat.

 

Cars not sold here can't be imported into Canada unless they're > 15 years old unfortunately.

If you would consider an SUV (which I think if you've not driven one of the new ones, you should at least do so before writing the whole class of cars off - they've made a lot of strides in the handling dept. lately), I don't know why you'd rule out the X3 and Q5.

The X3 I personally saw and measured its cargo space vs. the E61's, and it's just a bit less actually. But they are a lot lighter than your X5 and Q7, so their handling is quite good. Especially if you get them with adjustable suspension options. The Q5 for sure comes with a diesel engine - my friend has one and loves it.

The X3/Q5 are like 4200 lbs or so, the weight of our E61 vs. the X5/Q7 which are 5200 lbs. You'd feel the extra 25% weight I'm sure in the handling / acceleration / braking / fuel economy!

I'd even consider dropping the X3/Q5 a bit if you want lower clearance / less fender gap, and you're getting pretty darn close in handling then IMO to our E61.