Your comments

This is something that we have thought a lot about.

The problem is not assigning two project "types" to a project. The problem is the bug tracking aspect.

If you create a project in Lean Testing, automatically you have one bug base for this project, and you can create test plans for this project.

If your project is multiplatform - let's say, a website, an iOS app, and an Android app, you are most likely not going to log bugs for all these platforms in the same bug base (list of bugs) - that would quickly become a big, chaotic mess where you would have to filter extensively to figure out what bugs are related to what platform.

It would in fact be better to have 3 separate projects, one of the website, one for the iOS app, one for Android. This is our recommendation.

However if you feel strongly about this, and many others as well, we could change this.
You can't change your account type if you are Account Manager. The Account Manager is the creator of the organization. You can however, be a developer in someone else's organization, they just have to invite you as Developer.
That's a neat idea but we're a very small team, and doing something like this almost like another project in itself... We have to prioritize to best use our time.

I'll leave it open to see if there is significant interest.
This was one of our favorite features of the original overlook.io but there's an issue with many browsers deprecating iframes.

we'll look more into it
We cannot do this because we cannot know for sure that you are testing in the same browser in which you opened leantesting.com

you might have leantesting.com open in Chrome but are working in Safari
Not for long :-)