Why create a separate mobile page, when a responsive web based app can reduce the amount of UI shown to the user on smaller devices based on screen size, thus providing a better experience and less redesign for you.
Examples of this are: showing a smaller fly-out menu instead of the larger horizontal menu or hiding unnecessary areas that were only added to show extra content on larger screens.
Do some reading on progressive enhancement and mobile-first design to learn how to use the same design for multiple screens and adjust the content that is shown based on screen size. You’ll see alot mentioned about media queries/breakpoints which can be accomplish in Bubble with other actions that are similar to media queries.
This post is a good starting point: http://zurb.com/word/progressive-enhancement