Build a kit shop?

Not that I know of.

Many companies sell their collections individually, so you can pick and choose what you like to use (stickers, chipboard, embellishments, ephemera, brads, rub-ons, frames, journal cards, etc...). All the pieces of a collection coordinate.
Sometimes collections coordinate with other collections that the company makes (like Echo Park merchandise).
You could easily build your own kit.

I'm unaware of such company but encourage you to create your own page kits. While I don't subscribe to kits or gravitate toward American Crafts pattern paper brands, & therefore do not have or know the exact colors of your accumulated supplies, consider pairing the Elle's Studio pocket cards with your paper collections by color, theme, mood, or other trait, then do the same with stamp sets. Cardstock or solids can be added to tone down bright or busy patterned papers. Use other tools, such as punches, dies, stencils, inks, etc., to create embellishments (e.g. tags, labels) &/or backgrounds (e.g. stenciled, packaging technique). When starting with color, such as pale yellow, consider the color wheel (& online color palette generators - e.g. Canva). Perhaps combine pale yellow with white & grey for a modern color palette, lavender (complementary/opposite) for contrast, etc. Then, select pattern papers (using gallon/quart/pint proportions) & embellishments from your inventory (or create them using your tools) that match or coordinate with your chosen color palette. HTH. 

Yeah. It was the Secret Not Secret Kit Club. But you are right, I don't think she is in business anymore.