I am a new brewer and have only done LME Kits. I would like to try to make a sour but am not quite ready for an all grain brew. Are there any good recipes out there for a good Sour Ale using LME?
Sour brewing doesn't mean all grain brewing by any stretch. Sour beers start with wort just like anything other beer; how you get your wort doesn't matter. Of course all-grain affords you more control and options, but that's a statement for all brewing not sour beer specific.
Sour beer brewing and LME is perfectly fine. Pick a recipe that seems right for souring. Straight up Wheat LME alone would work perfectly fine as it usually 50/50 wheat and barley anyway. If you want more character you can steep specialty grains like you would any other LME/DME based beer. Just stay away from varieties that need mashing (an argument could be made here for the starches being good for the souring microbes, but that's a more complex topic for your first sour beer) Then pitch a souring culture blend.
Roeselare from Wyeast is a good place to start, but there are many other companies out there making souring blends now too. I've had the best luck combining Roeselare with blends from other companies in the same ferment.
If you're limited to LME you may want to just use lactic acid to sour a beer. This can be done post fermentation to taste.
You can use traditional bacteria with an LME beer but it would need to be inoculated.
True all grain sours are a big step in homebrew requiring a mash held at warm temp for several hours or at least a kettle with stable warm temps. Kettle souring keeps your fermentation free from souring bacteria.
If you ferment with bacteria & yeast you really need seperate fermentation equipment, racking tools and kegs just for sours.