hahah you should try the akg k545 next. you can find em for $200ish & people say that they are better than the momentums. another option is the NAD Visio HP50 at $300.
however, you probably won't be able to be going that budget friendly if you are looking to upgrade over the MDR-1Rs. You are looking to throw $200-$300 for sure if you are on the hunt for closed, portable sound rivaling the Momentums. I personally would skip the b&w in my opinion as the momentums are just as good if not better at $100 cheaper from my experience, and I'm sure that the k545 vs Visio option has sound quality rivaling it so I would look at those options first.
The NAD Visio HP50's are a good option, from what I've head there apparently really good for the price however here in Australia they are priced at $349.99 and I couldn't justify paying an extra $50. On the brighter side I got the MK2s at a steal price of $224.9 so I'm very happy. I prefer a warmer sound signature rather than a neutral sound because I can find more uses with a warmer sound like watching movies, playing games and of course listening to music.
If I was willing to spend more to have more than 1 headphone than I could justify buying a headphone with a more neutral sound to the MK2's like the HP50's but for my needs a warmer sound signature fits my budget well.