Yes there are, 2 - I found here on Amazon Ekobrew which had 4 star rating from 4722 reviewers and the Brew and Save with a 4.5 star rating from 351 reviewers, note neither of these units are compatible with B30 B130 B150 B155 Keurig units look them up hope this helps you.
I don't believe there is at the present, unfortunately. They want you to have to buy their K-cups. Assuming you want to use your own ground coffee you might make your own paper filters from larger ones. Whoever eventually comes out with small disposable paper filters to fit these machines will get a lot of business from people like you.
I do not have the small portable Keurig (your model number = ?), but if you are trying to use this filter, which is made by Keurig itself, I do not doubt that it doesn't fit. I do know that when using one of Keurig's filters in ANY Keurig machine, the black plastic piece that holds the prepackaged K-cups in the Keurig unit needs to be removed in order to accommodate the large grey (or brown) "holder" (or "adapter") piece that is included with the 3-piece My K-Cup refillable filters such as this. Keurig apparently DOES make different models of these 3-piece filters for different Keurig brewers.
The Solofill Chrome K3 that I referred to in this review (and that I have reviewed on Amazon) is a once-piece unit that is the SAME SIZE as a typical K-Cup. I'm assuming that this Solofill unit would fit directly into your unit as a replacement for a K-Cup (without the need to remove the black plastic insert that comes with all Keurig units). This is why the 1-piece units have become very popular. First, there is only one piece to clean, no pieces to "misplace", and most importantly, they make better coffee. The only caveat I can think of is that the Solofill comes with two flat rounded plastic "tabs" that protrude horizontally from the top of the filter. I'm assuming that the original black plastic inserts that Keurig provides with their brewers are all constructed the same, in that there are two "notches" on top which allow you to grip the K-Cup with two fingers and dispose of it. These same notches are where the Solofill's tabs fit into. You will need to have those same "notches" in your Keurig machine in order for the Solofill to fit, but I'm guessing that they're there, and that it shouldn't be a problem.
Not sure if this is the one you own, but I looked up the "Mini-Plus Personal Brewer" on Kohl's website, and also found the Keurig model refillable filter that fits into it. The product description for the refillable filter specifically says that it fits the "Mini-Plus Personal Brewer". Link to filter follows: (http://www.kohls.com/product/prd-174904/keurig-my-k-cup-reusable-coffee-filter.jsp). This looks a lot like the unit you asked about in this thread, so I'm thinking that you may be trying to use this unit without taking out the black plastic piece that is included with your Keurig BEFORE using the Keurig refillable filter. Or perhaps this is not the model Keurig you own. -M